Five different methods of using colored glass are demonstrated; some produce a uniformly colored object, others a splotchy or mottled effect. Glass artists today use whatever method best suits their aesthetic choices.
Glass that is colored by (1) impurities in the basic ingredients in the batch or (2) techniques of coloring glass by one of three main processes: (a) using a dissolved metallic oxide to impart a color throughout, (b) forming a dispersion of some substance in a colloidal state, and (c) suspending particles of pigments to form opaque colors.